Humpback whales blow bubbles around schools of fish to concentrate them for easier capture. It's called a bubble net, says David Wiley, research coordinator for Stellwagen Bank National Marine Sanctuary
, and it's visible as a ring of bubbles at the surface. Now, with underwater digital tracking tags and custom visualization software, whale researchers can see what the whales are doing underwater when they're bubble-netting.
footage: Dave Wiley, NOAA Permit #775-1600-10, Behaviour